Drafting instrument.



PATENTED MAYBO, 1905.

A. A. ALLEN. DNAPTING INSTRUMENT.

APPLICATION FILED JULY 7,1904.

2 SHEETS-SHEET 1.

.Miam

/m/.ENTON WITNESSES:

Amm/m8 No. 791,235( EATENTED MAY so, 1905.

- A. A. ALLEN.

DNAETNE INSTRUMENT.

APPLICATION FILED JULY 7,1904.

2 SHEETS--SHEET 2.

- UNITED STATES' .Patented May 30, 1905.

PATENT OFFICE;

DRAFTING INSTRUMENT.

SPECIFICATION forming part of Letters Patent N o. 791,235, dated May 30,19051 i Application tiled July 7, 1904. Serial No.'2l5,622.

To LZZ whom t may concern.-

Beit known that I, ALBERT ARTHUR ALLEN,

a citizen of the United States, and a resident' of Ortonville, in thecounty of Bigstone and 5 State of Minnesota, have invented a new andImproved Drafting Instrument, of lwhich the following is a full, clear,and exact description.

The object of the invention is to provide a new and improved draftinginstrument more especially designed for the use aoi." tinners, plumbers,and other mechanics in laying out the blanks for forming elbows, Ts, andother articles of sheet-metal and like material.l

The invention consists of novel features' and parts and combinations ofthe same, as will be more fully described hereinafter' and then pointedout in the claims. A practical embodiment of the invention isrepresented in the accompanying drawings, forming a part of thisspecilication, in which similar characters of reference indicatecorresponding parts in all the views.

Figure 1 is a side elevation of the divider radial divider for use inconnec-i tion with the peripheral divider for accurately laying outcurve cordinates for the joints of tapering bodies. Fig. 4t is a sideelevation of the same, parts being shown in section; and Fig. 5 is adiagrammatic plan view of the same, showing its use. The peripheraldivider B is arrangedvfor l obtaining ordinate points spaced equaldistances apart and dividing the periphery of a tubular body into equalparts. This divider may be used in connection with a diameterdivider ofany suitable or approved construction arranged for obtaining on thediameter of the tubular body the diametrical ordinate points. By drawingfrom these points it is evident that the curved coordinates are obtainedto`perrnit of conveniently and quickly drawing the desired curve.

The peripheral divider B lconsists of spacing-bars J, connected at theirupper ends to pivots K on the upper ends of the links of a lazy-tongs K,and the said spacing-bars J are l ymounted to slide inisuitable bearingsK2,

' opened or closed, s'o as held onthe pivots at the lower ends of thelinks of the lazy-tongs K. By the arrangement described the spacingfbarsJ are all spaced equal' distances apart, and by opening orclosing the 55 lazy-tongs the'spaces are increased or dimin? ished correspondingly,the lazy-tongs being to render the distance between thevend spacing-barsJ equal to`the developed or straightened 4 out periphery of 60 thetubular body under treatment.

The end spacing-bars J are mountedto slideA in bearings K3, held onpivots L, connecting the end links of the lazy-tongs K with each other,the said pivots L being in the shapeof 6 5 clamping-screws, having theirnuts L arranged for clamping thev several parts of the end links of thelazy-tongs together to hold the lazy-tongs in their adjusted position.

In order to lay out the joints for tapering 7o tubular. bodies, use ismade, in connection with the peripheral divider B, of a radial dividerN, shown in detail in Figs. 3, 4, and 5 and consisting of radial bars Nfulcrumed at one end on a pivot O and carrying at their ends slidablebearings P, adapted to be fastened to the arms N by set-screws P. Thebearings P are adapted to be engaged by the lower ends of thespacing-bars J, and the latter are secured to the bearings by set-screws8o P2. On the pivot O is held to turn a sleeve Q, in which is adjustablysecured by a setscrew Q' a rod R, provided at its free end with a head Rfor receiving a pencil or other marker S, adapted to be 'fastened inplace by 8 5 a set-screw R2. The lower end of the pivot O isperipherally provided with a gimletpoint O for conveniently securing thepivot in position in a hole on the sheet on which the layingout is to bedone, and on the upper 9o threaded .end of the said pivot O screws a nutO2 for clamping the several parts on the pivotl in place after the armsN are spread apart the desired distancein fan shape and according to theposition of the spacing-bars J, as will 95 bedreadily understood byreference to Figs. 3 an 5.

In order to layout the blanks for an elbow, for instance', the operator,by means of a suitable diametrical divider, lays outthe diameter I; O

other of the tubular body on the blank sheet of tin or other sheet metaland marks the diametrieal ordinate points. The operator now iigures outthe length of' the periphery of the tubular body and extends thesame atright angles to the diameter laid out on the sheet,

- as above explained, and then opens the lazytongs K, so that the endbars thereof cover the distance of the periphery. The operator now marksthe peripheral points on the sheet and then draws the coordinate linesfrom both points, the point of intersection of the said lines giving thecurve coordinate for forming the necessary curve. The operator now cutsalong the line of this curve and then bends the two pieces of the blankinto a tubular shape, so that the two pieces peripherally fit at themiter-joint along the curved edges, as will be readily understood.

vFor forming the blanks for a skew-T and in laying out an angular collar-1for the dome of a hot-air heater, &c., the operator proceeds insubstantially the same manner as above described.

In forming the joints Jfor tapering tubular bodies use is made of adiametrical divider A, as plainly indicated in Fig. 5, in connectionwith the peripheral divider B, having its bars J attached to thebearings P of vthe radial arms N, it being understood that the latterare spread apart by the said spacing-bars J an equal distance with thepivot O at the center, relative to which the divider A is radiallyarranged. The ordinates for the diametrical points are drawn by thepencil S, and the ordinates Jfor the peripheral points are radial alongthe arms N', so that the intersection of the lines drawn by the pencil Swith the arms N' gives the curve coordinates to allow the operator todraw the desired curve along which the sheet is cut to produce theproper joint.

It is understood that in the foregoing I have given but a few examplesof the use of the instrument, and it is evident that the instrument canbe readily employed for laying out various other curves required in theformation of tubular jointed bodies. v

While the divider B is especially designed for use as a peripheraldivider in laying out the blanks for forming tubular bodies, it is to beunderstood that the said divider can be employed for accurately dividingother objects or spaces into equal parts.

Having thus described my invention, I claim as new and desire to secureby Letters Patent-- 1. An instrument comprising a divider havingparallel spacing-bars, connected links having a iixed connection at oneend with the spacing-bars and a sliding connection at the other end withsaid bars, bearings in which the end spacing-bars are mounted to slide,the said bearings being held on pivots connecting certain of the linksof the lazytongs, and means for clamping the said links together to holdthe lazy-tongs in adjusted position.

2. An instrument comprising a divider having parallel spacing bars,connected links forming lazy-tongs and having pivots at thcir upper endsto which the upper ends of the spacing-bars are connected, bearings heldon pivots at the lower ends of the connected links and in which thespacing-bars are mounted to slide, and bearings in which the endspacing-bars are mounted to slide, the said bearings being held onpivots connecting the end links of the lazy-tongs with each other.

3. An instrulnent comprising a divider having parallel spacing-bars,connected links having a fixed and a sliding connection with the saidspacing-bars, bearings in which the end spacing-bars are mounted toslide and pivots connecting the parts of the end links together and onwhich the said bearings are held, thc said pivots being threaded andprovided with nuts for clamping the parts of thc end links together.

4. An instrument for obtaining curve coordinates, comprising a dividerhaving parallel spacing-bars, links having a iixed and a slidingconnection with the said spacing-bars, radial arms connected with thesaid spacingbars, and a pencil having its pivot coinciding withthe pivotof the radial arms.

5. An instrument for obtaining curve coordinates, comprising amultidivider having spacing-bars for dividing a line into a number ofequal parts, a pivot, radial arms fulcrumed on the said pivot andconnected with the bars of the said multidivider, and a scriberconsisting of a sleeve mounted on the pivot, a rod adjustably held onthe said sleeve and a scribing-point in the outer end of the rod.

6. An instrument for obtaining curve eoordinates, comprising amultidivider having spacing-bars for dividing a line into a number ofequal parts, a pivot, radial arms fulcrumed on the said pivot, bearingsadjustably held on the said radial arms and connected with the bars ofthe said multidivider, and a scriber consisting of a sleeve mounted onthe pivot, a rod adjustably held on the saidr sleeve and ascribing-point in the outer end of the rod.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ALBER" ARTHUR ALLEN.

Witnesses:

'IHos F. W ILsoN, I). E. Gemter.

IOO

IIO

